Strap-tensioning and severing tool

ABSTRACT

There is disclosed a hand tool for tensioning and severing straps of the type used in binding bundles of wires into cables, such straps including a connector adjacent one end thereof and the other end being free and adapted to be wrapped around the bundle to be bound and thereafter slid through the connector in a tightening movement, the tensioning and severing tool has a pair of jaws, one of which engages the connector and the other of which engages the free strap and extending beyond the connector, drive mechanism for tensioning the strap by moving the jaws apart and for thereafter actuating a strap-severing blade after the application of a predetermined force between the jaws, the tool of the present invention including mechanism for applying a restraining force upon the severing blade drive mechanism of a character which will prevent blade severing movement until the aforementioned predetermined tension is reached in the strap, after which means is provided that serves substantially instantaneously to relieve or reduce the restraining force in the blade drive mechanism, whereby the blade drive mechanism immediately and quickly actuates the blade to sever the strap; a combined trigger-type drive mechanism is provided which ensures that the same tension is produced in the strap at the cut-off no matter how the handle actuating the drive mechanism is gripped by the user; the blade drive mechanism is such that immediately upon cut-off, and before the blade actually cuts through the entire strap, the drive tension is released so that the blade never strikes the anvil or backup for the strap; finally, a novel adjustment mechanism is provided for adjusting the predetermined tension at which cut-off of the free strap end is effective.

United States Patent Caveney et al.

[ 51 May 9,1972

l54| STRAP-TENSIONING AND SEVERING TOOL [72] Inventors: Jack E. Caveney, Chicago; Roy A. Moody,

Flossmoor, both of 111.

[73] Assignee: Panduit C0rp., Tinley Park, 111.

[22] Filed: July 28, 1969 [21] Appl. No.: 870,190

Related US. Application Data [63] Continuation of Ser. No. 772,441, Oct. 21, 1968, abandoned, Continuation of Ser. No. 474,563, July 26, 1965, abandoned.

Primary Examiner-Charles W. Lanham Assislam Examiner-E. M, Combs Atwrne v-Prangley, Clayton, Mullin, Dithmar & Vogel [5 7] ABSTRACT There is disclosed a hand tool for tensioning and severing straps of the type used in binding bundles of wires into cables, such straps including a connector adjacent one end thereof and the other end being free and adapted to be wrapped around the bundle to be bound and thereafter slid through the connector in a tightening movement, the tensioning and severing tool has a pair of jaws, one of which engages the connector and the other of which engages the free strap and extending beyond the connector, drive mechanism for tensioning the strap by moving the jaws apart and for thereafter actuating a strap-severing blade after the application of a predetermined force between the jaws, the tool of the present invention including mechanism for applying a restraining force upon the severing blade drive mechanism of a character which will prevent blade severing movement until the aforementioned predetermined tension is reached in the strap, after which means is provided that serves substantially instantaneously to relieve or reduce the restraining force in the blade drive mechanism, whereby the blade drive mechanism immediately and quickly actuates the blade to sever the strap; a combined trigger-type drive mechanism is provided which ensures that the same tension is produced in the strap at the cut-off no matter how the handle actuating the drive mechanism is gripped by the user; the blade drive mechanism is such that immediately upon cut-off, and before the blade actually cuts through the entire strap, the drive tension is released so that the blade never strikes the anvil or backup for the strap; finally, a novel adjustment mechanism is provided for adjusting the predetermined tension at which cut-off of the free strap end is effectivev 27 Claims, 11 Drawing Figures PATENTEBHAY 91972 3,661,187 sum 2 0% 3 l i 40 f? PATENTEDMAY 9 I972 SHEET 3 OF 3 4 mm 0 I 6 B/ I FIG.

FIGJO STRAP-TENSIONING AND SEVERING TOOL This application is a continuation of Ser. No. 772,441, filed Oct. 21, 1968, which was a continuation of Ser. No. 474,563, filed July 26, 1965, now both abandoned.

The present invention relates to the art of strap tensioning and severing tools of the hand-tool type, and particularly to a highly-improved hand tool for tensioning and securing flexible binder straps around bundles of wire or other objects.

In recent years there has been a very material increase in the production, repair, and maintenance of complicated electrical and electronic installations, and the industry for some time has been seeking improved means by which bundles of wires and electrical leads may be quickly and economically secured and bound together. Substantial improvements have been made in flexible binder straps for this purpose, and U.S. Pat. No. 3,197,829 issued to the present applicants on Aug. 3, 1965, illustrates and claims one such strap. Binder straps of this general kind comprise a longitudinally-extending strap having a connector means adjacent one end thereof, with the other end being free and adapted to be wrapped around the object or bundle to be bound and thereupon to be slid through the connector in a tightening or binding movement. Connectors or straps of this kind customarily are provided with latching or securing structure for holding or retaining the strap in its tightened condition once the strap has been placed in the tightened or tensioned condition. For the sake of neatness, and, in order to reduce the number of loose ends that may exist in conjunction with the circuitry, it is desirable, once the strap has been tightened about the bundle, to cut or sever the free strap end which extends from the connector portion of the strap assembly.

One of the important objects of the present invention is to provide a highly-improved hand tool for quickly and economically applying flexible straps of the foregoing kind to bundles of wire and the like and for thereupon severing the free or loose ends of the straps, the tool having highly-improved means for applying successive straps at uniform predetermined tensions, no matter how the handle actuating the drive mechanism is gripped by the user.

Another important object of the present invention is to provide a strap tensioning and severing tool of the kind just stated, having a pair of jaws for progressively tensioning the strap, drive mechanism for actuating a strap-severing blade, and means for applying force to both the jaws and the severing blade drive mechanism, wherein additional means are em ployed for applying restraining force upon the severing blade drive mechanism to prevent blade severing movement thereof until a predetermined tension is reached in the strap, and wherein further means are included for substantially instantaneously relieving or reducing the restraining force on the blade drive mechanism when the predetermined tension in the strap is reached, whereby the blade drive mechanism thereupon immediately and quickly actuates the blade to sever the strap, thus ensuring that successively applied straps will all be tensioned accurately and uniformly.

Another important object of the present invention is to provide a strap tensioning and severing tool, of the kind referred to above, which uniformly tensions successively applied straps regardless of how the tool is held in the hand.

Still another important object of the present invention is to provide, in a hand tool having the attributes described above, relatively simple and highly-improved mechanism for bringing about the tensioning and severing of the straps.

Still another object of the present invention is to provide in hand tools of the foregoing kind improved means for selective ly varying the predetermined tension in the straps applied.

Yet another object of the invention is to provide a strap tensioning and severing tool of the foregoing kind which is relatively inexpensive to manufacture, entirely reliable in its use, very durable, and comfortable and convenient for use.

These and other objects and advantages of the present invention will be apparent from the following description of a preferred embodiment thereof, with certain variations, taken with the drawings wherein:

FIG. 1 is a side elevation view of a tool embodying the present invention, the tool being illustrated in a condition wherein it has received a binder strap of the general kind referred to above and the tool is about to be actuated to tighten or tension the strap about a bundle;

FIG. 2 is a top plan view of the tool, with the strap and bundle being omitted;

FIG. 3 is an end view of the tool, as seen from the right in FIG. 1;

FIG. 4 is a fragmentary cross-sectional view taken through the tool substantially along the line 4-4 in FIG. 1;

FIG. 5 is an enlarged end view of the tool taken substantially along the line 5-5 in FIG. 1, with the strap being omitted, and with an end plate on the tool being partially cut away so as to show a strap-severing blade which is located on the forward end of the tool beneath the plate;

FIG. 6 is a side view of the tool in the same condition illustrated in FIG. 1, but with the strap omitted and with a side plate on the handle portion of the tool removed to illustrate the parts on the interior of the tool, certain of the parts of the tool being shown in cross section for better illustration;

FIG. 7 is a view of the tool similar to FIG. 6, but showing the positions of the parts of the tool after the tool has been actuated to tension the strap and showing the positions of the parts of the tool prior to severance of the strap, certain parts of the tool being cut away for better illustration;

FIG. 8 is a view like FIG. 7, but showing the parts inthe positions which they occupy immediately after the severing blade has been actuated, or at the instant it is actuated, to cut I the strap;

FIG. 9 is a fragmentary elevational view of the lower portion of the handle of the tool, with the handle plate removed, and with a tensioning selector moved to a position different from that illustrated in the preceding figures, so as to effectively change the tension at which the strap will be severed, FIG. 9 also illustrating a modification used for preventing inadvertent variation of a selected tension;

FIG. 10 is a fragmentary view of the lower portion of the handle of the tool, with the handle plate removed to illustrate a magnetic variation of the means for applying restraining force to the severing blade drive mechanism and for substantially instantaneously relieving or reducing that force upon the attainment of the predetermined tension in the strap, whereupon the blade drive mechanism will actuate the blade to sever the strap; and

FIG. 11 is a view like FIG. 10 showing a pneumatic variation for accomplishing the same purpose.

Referring initially to FIGS. l-6, it will be seen that the present tool, in the embodiment shown, is provided with a configuration resembling that of a gun having a handle portion and a forwardly-projecting portion somewhat similar in position to a gun barrel. The main body portion of the gun-shaped tool is comprised of a casting 20 of aluminum or the like having a handle portion 21 and a forwardly-projecting portion 22. The handle portion 21 is recessed so as to provide a side wall 23. The rear peripheral portion of the handle portion 21 is defined by a laterally-extending flange 24 which extends downwardly and merges with a lower wall flange 25. This lower flange 25, on the other hand, extends forwardly and merges with the lower end of a similar flange 26 which defines the forward periphery of the handle portion 21 of the gun, the upper end of the flange 26 terminating at 27. As best seen in FIG. 6, the upper end of the rear flange 24 merges with a rearwardly'directed flange 28, the rear end of which merges with an upstanding abutment flange 29. The upper end of the flange 29, in turn, merges with a forwardly directed flange 30. The forwardmost end of the flange 30 is downturned at 31 and terminates at 32. It will be observed that the flanges 28, 29, and 30 provide a socket-like configuration for receiving a relatively-heavy compression spring 33.

The handle portion of the tool just described is covered by a cover plate 34 having intumed lateral flanges 35 which mate with and have the same configuration as the previouslydescribed flanges 24, 25, 26, 28, 29, 30 and 31. Suitable bosses 36 and 37 are formed integrally with the wall 23 and are suitably threaded to receive screws 38 and 39 which extend through openings in the plate 34 for securing the plate in fixed position on the flanges 24, 25, 26, 28, 29, and 31. The plate 34 thus encloses the handle portion of the gun 'and the parts located therein.

The forwardly-projecting portion 22 of the casting is generally of rectangular cross section (See FIG. 4), with a longitudinally-extending slot 40 formed therein for slidably receiving a longitudinally-extending tension rod 41, later to be described.

The forwardmost end of the forwardly-projecting portion 22 of the casting has a laterally-projecting boss formed thereon having a flat vertically-extending forward face '51 thereon and a sloping face 52 (FIG. 7) formed on its rear side. Above the triangular-shaped boss, the forwardmost portion of the forwardly-projecting portion 22 of the basic casting of the tool has a laterally-projecting backup boss 53 formed thereon, the under surface of which overhangs the triangularly-shaped boss 50, thus defining a slot 54 (FIG. 5) for receiving the free end 55 of a strap designated generally by the numeral 56.

As previously suggested, the strap 56 may be of a construction like or similar to that illustrated in U.S. Pat. No. 3,197,829 issued to the present applicants. The strap has a connector portion 57 fixed to one end 58 of the strap, with the free end of the strap 55 capable of being wrapped around the bundle 59 and then passed through an opening in the connector 57, so as to form a closed loop about the bundle, as illustrated in FIG. 1. The loop formed by the strap, in straps of this kind, is tightened by pulling on the free end 55 of the strap while preferably restraining the end portion 58 and the connector 57 against movement. The connector 57, in straps of this kind, is provided with latching means acting upon that portion of the free end 55 of the strap within the connector, so as to prevent a strap loop from loosening, once the loop has been tightened.

The tensioning rod 41 is longitudinally slidably disposed in the slot 40, as previously described, and the rod 41 is preferably provided with a longitudinally-extending slot 60 through which there extends a screw 61 which is threaded into the element 22 and has a head 62 which overlies the tension rod 41 along the lateral sides of the slot 60. The tension rod 41 is thus retained in the slot 40. The forward end of the tension rod 41 carries a laterally-extending screw 63 upon which there is pivotally mounted a gripper 64 having teeth 65 formed on its upper side for gripping the under side of the free end 55 of the strap 56. The back side of the gripper 64 is provided with a spring, not shown, having one end fixed to the tension rod 41 and the other end bearing against the wall of a recess in the gripper 64, so as continuously to urge the gripper 64 to be pivoted in the counterclockwise direction, as viewed in FIG. 1. This means for causing a gripping pawl, such as the gripper 64, constantly to be urged in a direction about an axis, such as that provided by the screw 63, is well-known, and for this reason it is believed unnecessary to illustrate the spring just referred to. When the tension rod 41 is in its forward position, as illustrated in FIG. 1, the forward side 66 of the gripper 64 bears against the sloping wall 52 of the triangular boss 50, thus camming the gripper 64 to the normal position thereof seen in FIGS. 1 and 6.

Above the position of the gripper 64, the tension rod 41 has a laterally-projecting backup lug 67 forward thereon which overhangs the gripper 64 and serves to back up or support the upper side of the free end 55 of the strap 56 when the teeth 65 of the gripper 64 forcefully engage the free end 55 of the strap.

A forwardly-projecting lever arm 70 is pivotally mounted on the side of the element 22, below the level of the tension rod 41, by means of a pin 71. If desired, the pin may be press-fitted in a suitable opening provided in the element 22 and rotatably received in a corresponding opening in the lever arm 70, as seen in FIG. 4. The forward end of the lever arm 70 extends to a position spaced somewhat below the triangularly-shaped boss 50, and the forward extremity of the lever arm is provided with a pair of forwardly-projecting fingers 72 and 73 which are received in two corresponding slots 74 and 75 formed in a cutter blade 76. The upper edge 77 of the cutter blade is sharpened to provide a knife edge, and the body of the cutter blade 76 is slidably received on the front face of the triangularly-shaped boss 50. The body of the cutter blade is provided with an elongated slot 78 for accommodating a screw 79 which extends through the slot 78 and is threaded into the triangular boss 50. The cutter blade 76 is slidably retained in this position by a cover plate 80 which is secured to the front of the too] by the screw 79 and by another screw 81 which is threaded into the forward end of the element 22, as best seen in FIG. 5. The plate 80 has a slot formed therein which mates with the slot 54 previously referred to. The normal positions of the lever arm 70 and the cutter blade 76 are illustrated in FIGS. 1 and 6, but it will be appreciated that, if and when the lever arm 70 is pivoted about the pin 71 in the clockwise direction, as viewed in these figures, the cutter blade 76 will be slidably raised so as to bring its knife-like upper edge 77 into cutting contact with the free-end portion 55 of the strap 56.

The tool is provided with a forwardly and downwardly extending trigger or actuator handle 85, the exposed portion of which, if desired, may be suitably covered by a suitable plastic or pliable sheath 86. The lower portion of the actuator handle may comprise a transverse web 87 having rearwardly-directed flanges 88 and 89 formed thereon. The web 87 terminates at 90, but the two flanges 88 and 89 extend upwardly between the wall 23 of the handle portion of the tool and coverplate 34. At their upper ends, the two flanges 88 and 89, which are laterally spaced apart, are pivotally mounted on a pin 91. One end of the pin 91 is received in an opening in the wall 23 of the handle portion of the main frame or casting of the tool, and the other end of the pin 91 is received in an opening 92 in the handle plate 34, as seen in FIG. 1. This pin 91 provides a fixed axis for the actuator handle or trigger and for certain other parts of the tool which will later be described.

Between the flanges 88 and 89 of the trigger or actuator handle 85 there is an actuator link 95. The lower portion of the actuator link 95 is secured in place by a transverse pin 96 which is carried between the flanges 88 and 89. The forward edge of the lower portion of the actuator link 95 may lie against the inner surface of the web 87 of the trigger 85. The upper portion of the actuator link 95 has a somewhat dog-leg configuration (See FIG. 7), and the upper extremity of the actuator link is pivotally mounted upon the fixed pin 91. Intermediate the pins 91 and 96, the actuator link 95 has a pin 97 fixed thereon which pivotally receives one end of a drive link 98. The other end of the drive link 98 is pivotally received on a pin 99 which is fixed to a lever link 100 midway between the opposite ends of the latter. The upper end of the lever link 100 has a pin 101 fixed thereon which rides in a vertically-elongated slot 102 formed in the rear end of the tension rod 41. The lower end of the lever link 100, on the other hand, is pivotally mounted upon a pin 103 which is fixed in and extends laterally between a pair of identical, spaced-apart link plates 104 and 105, both of which will be referred to at some length hereinafter.

The spring 33, which is retained in the socket-like configuration provided by the flanges 28, 29 and 30 at the upper rear portion of the handle of the tool, has already been referred to. This spring 33 may be sometimes referred to hereinafter as a return spring. The rear end of this spring 33 bears against the inner surface of the flange 29, and the forward end of the spring forcefully bears against an end of a return yoke designated generally by the numeral 111. This return yoke 111 has a pair of forwardly-projecting arms 112 and 113 (the latter of which is shown only in FIG. 7). The forwardmost ends of the yoke arms 112 and 113 are respectively pivotally secured, as by a pair of pins 114, to the upper portions of the flanges 88 and 89 of the trigger or actuator handle 85 somewhat below the position of the fixed pivot pin 91. It will thus be understood that the return spring 33, through the yoke 111, constantly urges the trigger or actuator arm 85, in the clockwise direction, as viewed in FIGS. 1 and 6.

It has previously been pointed out that the lower end of the lever link 100 is pivotally mounted upon a pin 103 which is fixed in and extends between the spaced-apart link plates 104 and 105. These link plates 104 and 105 are disposed respectively immediately inside the upper portions of the two flanges 88 and 89 as will be fully understood from a careful study of FIGS. 6 and 7. The link plates 104 and 105, at their forwardmost ends, have a pin 120 fixed therein and extending laterally therebetween. This pin is received in a rearwardly-opening slot 121 formed in the rear end of the lever arm 70 which actuates the strap-severing blade 76 (See FIG. 6). The two link plates are of identical shape, and the forward and upper portion of each link plate has a somewhat dog-leg configuration, each link plate at its upper extremity being pivotally mounted upon the fixed pin 91.

The lower right-end portions of the two link plates 104 and 105 have a pin 122 fixed therein and extending therebetween, and the pin 122 rotatably carries a roller 123 between the link plates. This roller co-operates with a pivoted cam or detent 125. The cam member or detent 125 is pivotally mounted upon a pin 126, one end of which is received in an opening in a boss (not shown) formed on the inner surface of the plate 23 which forms one side of the handle portion of the tool. The other end of the pin 126 (the end closest to the eye in FIGS. 6 and 7) is received in an opening provided in a similar boss formed on the inner surface of the handle cover plate 34. It will thus be understood that the pin 126 provides a fixed axis about which the cam member or detent 125 may pivot. The upper surface of the cam member or detent 125 is provided with a cylindrically-concave recess 127 having a radius only slightly larger than the radius of the roller 123, the recess 127 being slightly to the right of the pin 126, as seen in FIGS. 6 and 7. The right-hand extremity of the cam member or detent 125 has an upwardly-extending portion 128 formed thereon which terminates in a sloping cam surface 129. The opposite end of the cam member or detent 125 is pivotally mounted upon a pin 130 which extends between and is carried by the upper end portions of a pair of arms 131 and 132 of a tension yoke designated generally by the numeral 133. The lower ends of the two arms 131 and 132 are joined together by a web 134. Between the two arms 131 and 132 there is slidably mounted a tension block 135, the opposite sides of the block being provided with longitudinally-extending recesses 136 which slidably receive the two arms 131 and 132 and thus serve to guide the block between the arms. The block 135 has a recess 137 therein which opens at the bottom end of the block. Thus, as seen in FIG. 6, the upper end of the block is, in effect, closed by a transverse web 138. The inner surface of this web 138 has an apertured boss 139 formed thereon which is threaded to receive the upper end portion of a threaded tensioning rod 140. The lower end portion of this tensioning rod 140 extends through an opening in the web 134 of the yoke 133 and through a similar opening in the flange 25 at the bottom of the handle of the tool. The lower extremity of the tensioning rod 140 threadedly receives a transverse pin 150, the pin 150 being secured against rotation upon the tensioning rod 140 by a second transverse pin 151.

A compression spring 155 has its upper end disposed in the cavity 137 within the tension block 135, with the uppermost end of the spring 155 bearing against the inner surface of the web 138. The lower end of the spring 155 bears against the upper surface of the web 134 which extends between the yoke arms 131 and 132.

The opposite ends of the pin 150, which is secured upon the lowermost end of the tensioning rod 140, respectively receive a pair of wings 160 and 161 of an adjustment knob designated generally by the numeral 162, the two wings 160 and 161 being joined by a transverse web 163. The outer end of each wing 161 and 162 is curved, as at 164, to provide a camming surface, while flat surfaces 165 and 166 are provided on opposite sides of each wing. Eachof the wings 160 and 161 adjacent its flat surface 165 is provided with an outwardlydirected ledge 167, and each is provided with an outwardlyextending ledge 168 adjacent its flat edge 166. In FIGS. 1, 3,

6, 7, and 8, the flat surfaces 165 of the wings 160 and 161 of to pull constantly downwardly on the pin 130, thus tending.

forcefully to pivot the detent or cam member 125 in a counterclockwise direction, as seen in the figuresnThe roller 123 on the link plates 104 and 105 normally resides in the recess 127 of the cam member or detent 125. Thus, the pivoting force applied to the detent or cam member 125is transmitted and applied as a predetermined restraining force on the link plates 104 and 105, as will be more fully explained hereinafter.

In the operation of the tool illustrated in FIGS. 1-8, the strap 56 is looped about a bundle of wire or the like 59, with the free end 55 of the strap fed through the connector 57. When the operator is ready to tension the strap about the bundle and sever the free end 55, the free end 55 is slipped laterally into the slot 54 at the nose or front of the tool, as illustrated in FIG. 1. The tool, in its normal condition, will be as seen in FIGS. 1 and 6, with the gripper 64 cammed by the triangular boss 50 to an openposition, permitting easy receipt of the free end 55 of --the strap between the gripper and the backup member 67 on the tension rod 41. Having deposited the strap in the tool in the fashion illustrated in FIG. 1, the operator grips the tool in his hand and pulls or squeezes upon the trigger or actuator handle 85, thereby causing the latter to be pivoted in a counterclockwise direction about the fixed pin 91. This motion of the trigger 85, and the force applied thereto, is transmitted by the actuator link 95, the pin 97, the drive link 98, and the pin 99 to the lever link 100, thereby causing the latter to pivot in a clockwise direction about the pin 103. This force applied to the lever link and the resultant movement thereof causes the pin 101 at the upper end of the drive link 100 to pull the tension rod 41 to the right, as viewed in the figures. Disengagement of the forward surface 66 of the gripper 64 from the triangularly-shaped boss 50 permits the gripper immediately to rotate in a counterclockwise direction, thereby causing its teeth 65 to grip the under side of the free end 55 of the strap. Continued motion of the tension rod 41 toward the right causes the connector portion 57 of the strap to bear against the forward surface of the front plate of the tool, whereupon further motion of the tension rod 41 toward the right tightens the strap 56 about the bundle 59. As the tension builds up in the free end 55 of the strap, between the jaw provided by the front end portion of the tool and the jaw provided by the gripper 64 and the backup 67, it will be appreciated that the lateral force exerted upon the pin 103 at the lower end of the lever link will continue to build up, this force being applied by the pin 103 to the two link plates 104 and 105. It will also, be remembered that the link plates 104 and are pivotally mounted upon the pin 91. During this build-up of force upon the link plates 104 and 105, these link plates would pivot about the pin 91 if it were not for the restraining force being applied to the link plates by the detent or cam member However, as the tension in the strap 55 reaches a predetermined maximum, the lateral force on the pin 103 and upon the link plates 104 and 105 will reach a point at which the restraining force applied by the detent or cam member 125 is overcome. At the moment this occurs, the roller 123 will cam the detent or cam member 125 ina clockwise direction toward the position thereof illustrated in FIG. 8, during which motion the roller 123 will snap out of the recess 127, thereby substantially instantaneously relieving or reducing the restraining force on the link plates 104 and 105 and permitting the link plates 104 and 105 substantially instantly to pivot from their normal position to the position thereof illustrated in FIG. 8. This counterclockwise pivotation of the link plates 104 and 105 about the pin 91 causes the transverse pin 120 at the forward extremities of the link plates to pivot the lever arm 70 in a clockwise direction about the pin 71 to the position shown in FIG. 8, thereby substantially instantaneously raising the blade 76 and causing the upper edge 77 thereof to sever the free end portion 55 of the strap.

At the moment severing of the strap occurs, the tension rod 41 will be substantially instantaneously and rapidly drawn further to the right, bringing the rear sloping edge of the gripper 64 into contact with the head 62 of the screw 61, thereby causing the gripper 64 momentarily to be cammed to its normal position, as shown by the broken lines in FIG. 8, thereby releasing from its grip the severed end 55 of the strap. This action will normally cause the severed end 55 of the strap to be thrown out of the grip of the gripper 64.

Instantly, after the strap portion 55 has been severed, thereby causing the lateral force applied by the pin 103 to the link plates 104 and 105 to be substantially reduced, the sloping surface 129 of the detent or cam member 125 will cam the roller 123 in a returning motion back into the cylindrical concave recess 127, thus immediately returning the link plates 104 and 105 to their normal position. This returning motion of the link plates 104 and 105 instantly returns the lever arm 70 and the blade 76 to their normal positions. The operator will also release his grip on the trigger 85, thereby permitting the return spring 33, through the action of the return yoke 1 l l, to return the trigger 85 to its normal position, as illustrated in FIGS. 1 and 6. This restoration of the trigger 85 to its normal position causes the drive link 98 and the lever link 100 to return to the positions thereof seen in FIG. 6. The returning motion of the lever link 100 moves the tension rod 41 to the left and to its normal position illustrated in FIGS. 1 and 6, thereby causing the gripper 64 to be cammed to its normal position by its contact with the sloping surface 52 of the triangularly-shaped boss 50.

It will be appreciated that, by rotating the tension adjustment knob 162 about the axis of the tensioning rod 140, the tension block 135 will be selectively raised or lowered, thereby selectively varying the compression of the spring 155, and thus selectively varying the restraining force applied by the cam member or detent 125 upon the link plates 104 and 105. This selective variation of the restraining force applied to the link plates effectively selectively varies the predetermined tension that will be applied to the free end 55 of the strap 56 at the time ofits severance. If desired, the tension block 135 may have an index line 135a (FIG. 1) scribed thereon. This scribe line may be made visible to the operator through an opening 34a provided in the handle plate 34, the elevation of the scribe line 135a in the window serving to indicate the restraining force being applied to the link plates 104 and 105, and thus the predetermined tension that will be produced in the strap 56. If desired, reference or index lines 34b may be scribed on the outer surface of the handle plate 34 adjacent the window 34a, as illustrated in FIG. 1.

Another way of selectively varying the restraining force applied to the link plates 104 and 105, is to pivot the adjustment knob 162 180 about the axis of the pin 150. It will be observed that the pin 150 is eccentrically located in the adjustment knob 162 (FIG. 6). Thus, the adjustment knob may be pivoted in a counterclockwise direction about the pin 150 from the position of the knob illustrated in FIGS. 1, 6, 7, and 8 to the position thereof illustrated in FIG. 9. During this pivotal movement, the cam surfaces 164 on the wings 160 and 161 of the knob bear on the under surface of the flange of the handle of the tool, thereby progressively camming the pin 150 from the position thereof shown in FIG. 6 to the position thereof shown in FIG. 9. This lowering of the position of the pin 150 lowers the tension block 135, thereby increasing the force of the spring 155 on the yoke 133 and thus increasing the predetermined restraining force applied to the link plates 104 and 105. This, in turn, increases the predetermined force that will be produced in the strap between the gripper 64 and the cover plate 'at the instant before severing occurs.

In FIG. 9, the adjustment knob 162 is shown to have been turned about the axis of the tension rod 140, from the position of the knob illustrated in FIG. 6. With the adjustment knob in the position seen in FIG. 9, a set screw may be threaded into a suitable opening provided in the flange 25 so as to prevent an operator from inadvertently rotating the knob 162 about the axis of the tension rod 140, while, at the same time, permitting the knob to be rotated from a high-tension position to a low-tension position, and vice versa, about the axis of the pin 150. If it is desired that the adjustment knob 162 not be permitted to be moved in any adjusting fashion, a headed screw may be employed in place of the screw 180, with the head overlying the ledge 168 on the adjustment knob.

In FIG. 10, there is illustrated a magnetic variation employed in the tool of the present invention, for applying a predetermined restraining force to the link plates 104 and 105. In this variation, the roller 123 is omitted, and in its place a link is pivotally mounted upon the pin 129 between the link plates. The lower end of the link 190 is pivotally secured to a flapper member 191 by a pin 192. The flapper member 191, in turn, is pivotally mounted upon a pin 193 fixed between a pair of bosses 194 formed on the inner surface of the flange 26 of the handle portion of the tool. The flapper member 191, like the handle portion of the tool, may be formed of nonmagnetic metal, such as aluminum, and the lower surface of the flapper member 191 may have applied thereto, as by screws, an armature plate 195 of magnetic material, such as iron, adapted to coact with a permanent magnet 196 suitably installed and held in place in the lower portion of the interior of the handle by bosses 197 and 198. In this construction, it will be appreciated that the permanent magnet 196, through the plate 195, the flapper member 191, and the link 190, will apply a predetermined restraining force to the link plates 104 and 105, in substantially'the same fashion as the structure previously described. Similarly, when the lateral force applied by the pin 103 upon the link plates 104 and 105 becomes sufficiently great during the tensioning of a strap, the restraining force will suddenly be overcome, thereby pulling the flapper member 191 and its plate 195 in a pivoting motion upwardly away from'the magnet 196, thus permitting the link plates substantially instantly to pivot about the pin 91, thereby to actuate the severing blade.

A further revision is illustrated in FIG. 11, wherein the pin 122 has a link 200 pivotally mounted thereon, the lower end of which is pivotally mounted upon a wrist pin 201 of a piston 202. This piston 202 is slidably mounted in a cylinder 203 contained in the lowermost portion of the handle of the tool, the cylinder being provided with one or more sealing rings 204. The lower end of the cylinder has a tapered valve seat 205 formed therein, with the lower end of the concave valve seat joining a downwardly-extending opening 206 which extends through the headed cylinder and through the flange 25 of the handle of the tool. A valve member 207 is seated in the valve seat. A valve stem 208 extends from the valve through the opening 206 and to the exterior of the tool. The outer extremity of the valve stem 208 is threaded to receive an adjustment nut 209, and a compression spring 210 is disposed between the nut 209 and the under surface of the flange 25. The spring 210 serves constantly to urge the valve member 207 into closed position in the valve seat 205. A one-way ball-check valve 211 is also installed in a passage extending from the interior of the cylinder to the exterior of the tool, with a compression spring 212 urging the ball to its closed position in a valve seat, as illustrated in FIG. 11. It will be understood that this variation illustrated in FIG. 11 will also serve to apply a predetermined restraining force upon the link plates 104 and 105 to cause a predetermined tension to be reached in a strap end before it is severed. As the strap end is tensioned, the lateral force, as previously stated, applied by the pin 103 to the link plates 104 and 105, will tend to cause the plates to pivot and thus, through the link 200, to raise the piston 202 in the cylinder 203. This tendency will produce a vacuum between the head of the piston and the head of the cylinder, thereby producing and causing a predetermined restraining force to be applied to the link plates 104 and 105. As the force upon the plates 104 and 105 is increased by the pin 103, the vacuum within the cylinder will reach a point at which the valve 207 will be raised, thereby substantially instantaneously permitting air to flow through the passage 206 and into the cylinder, thereby nullifying the vacuum, and reducing or relieving the restraining force upon the link plates 104 and 105, thus permitting the link plates to actuate the cutter blade 76. Upon severance of the strap end 55, and upon return of the parts of the tool to their original positions by reason of the force of the spring 33, the piston 202 will be restored to its normal position, as illustrated in FIG. 1 1. During this restoring movement of the piston, the air in the cylinder will be expelled through the passage in which the ball-check valve 211 is located.

In the case of the pneumatic means shown in FIG. 1 1 for applying a restraining force to the link plates 104 and 105, it will be appreciated that this restraining force may be selectively varied, and the predetermined tension to be achieved in the strap 56 likewise to be varied, by selective adjustment of the nut 209 on the valve stem 208. Rotation of the nut 209 on the valve stem will vary the compression of the spring 210 and thus will vary the point at which the valve member 207 will pop upwardly into an opening position so as substantially instantaneously to reduce or relive the restraining force on the link plates 104 and 105, thereby permitting pivotation of the link plates about the pin 91 to actuate the cutter blade 76 in a strap-cutting motion.

lt was stated at the outset in this specification that one of the objects of the present invention is to provide a hand tool for tensioning and severing straps which will produce uniformity of tension in successively-applied straps, regardless of how the tool is held in the hand. A consideration of the forces exerted on the different parts of the tool illustrated in the present drawings and described above will reveal that this objective has been accomplished. Indeed applicants know of no prior hand-operated tool, for tensioning and automatically severing straps, having this highly-desirable characteristic. In the prior hand-operated tools known to applicants, the tension in the strap, at the time of its severance, will vary, depending upon where the finger force is applied to the actuating handle or handles and depending upon variations in the compression in the handle return springs at the time strap severance takes place. Neither of these deficiencies exists in the tool of the present invention. This will be understood from the above description and illustrations and when particular regard is given to the forces acting on the lever link 100. It will be seen that the force applied by the pin 101 corresponds to strap tension, and it will also be seen that, for a particular adjustment of the knob 162, strap severance will occur every time the force exerted by the pin 103 on the link plates 104 and 105 reaches a particular level. It will also be seen that the forces on the pins 101 and 103 result solely from the actuating force applied to the pin 99, and the sum of the forces on the pins 101 and 103 is equal to the force applied to pin 99. Since there is a fixed or constant dimensional relationship between all three of these pins, the force relationship between them is also fixed. For example, with the pin 99 located midway between the pins 101 and 103, as is the case in the embodiment of the invention here shown, the force on the pin 101 is equal to the force on the pin 103, and each force will be one-half of the force on pin 99. Therefore, the strap tension is always the same at strap severance for a particular setting of the adjustment knob 162, and the strap tension at cut-off is not dependent on the source of actuating force applied through the pin 99. It is equally true, therefore, that the strap tension at which cut-off occurs will not be changed by the application of finger force at different elevations on the trigger or actuating handle 85, nor by any force variations that may be produced by means, such as the return spring 33, for returning the trigger to its original position.

The other objects first stated above are also attained by the tool of the present invention. The tool maybe relatively light in weight, it is comfortable and convenient to use, and binding straps may be applied to bundles of wire or the like, at uniform selected tensions, rapidly and easily with the use of the tool. Furthermore, the tool is substantially foolproof, relatively simple of construction, very durable, and relatively easy to manufacture. Indeed, the durability of the tool is enchanced by the fact that the tool inherently tends to avoid hammering the strap-cutting parts of the tool against other parts thereof as the strap severing iscompleted. On the contrary, although the blade 76 moves very rapidly during the cutting stroke, it will be appreciated that during thefraction of a second before severing of the tensioned strap end 55 is complete, the tensioned strap will begin to part, thereby permitting-the tension rod 41 to move slightly to the right as viewed in the figures. This movement instantaneously reduces the forces on the pins 101 and 103, and thus on the lever arm and the blade, and tends to reduce or avoid hammering effects on thelever arm and blade as they reach the end of their cutting stroke.

While the invention has been illustrated and described with respect to a preferred embodiment thereof, with certain variations, it is to be understood that various changes and modifications may be made therein without de'parting from the inventive concept underlying the invention. Therefore, the invention is not to be limited, except as is necessary, by the prior art and the scope of the appended claims.

What is claimed is:

1. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, linkage operatively connected to said gripper and. said blade, an actuator operatively connected to said linkage, said linkage having a strap-tensioning mode wherein the force exerted by said actuator through said linkage is applied to said gripper for moving said gripper in a strap-tensioning direction and having a strap-severing mode wherein force exerted by said actuator through said linkage is applied to said blade for moving said blade in a strap-severing direction, and restrainingmeansfor holding said linkage in said strap-tensioning mode until a predetermined tension is reached in the length of the strap between the first and second points thereon whereupon said linkage is shifted into said strap-severing mode thereof, means mounting said actuator for movement thereof between a rest position and a fully-actuated position along a predetermined regular path with respect to said abutment, the predetermined path of travel of said actuator during said strap tensioning mode of said linkage being identical to the predetermined path of travel of said actuator during said strap-severing mode of said linkage thereby to provide'a single predeterminedpath of travel for said actuator between said rest position and said fully actuated position thereof, whereby said restraining means is overcome when a predetermined-tension is produced in the portion of the strap between the first and second points thereon thereafter to shift said linkagefrom the strap-tensioning mode thereof to the strap-severing-rnode thereof to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.

2. The binder straptensioning and severing tool set forth in claim 1, wherein the predetermined path of said actuator from said rest position to said fully-actuated position is a pivotal path about a point fixed with respect to said abutment.

3. The binder strap tensioning and severing tool set forthin claim 1, wherein said restraining means is adjustable so as to adjust the predetermined tension in the portion of the strap between the first and second points thereon causing actuation of said blade to effect severing of thestrap.

4. The binder strap tensioning and severing tool set forth in claim 1, and further comprising releasable interconnecting means between said linkage and said restraining means, said releasable interconnecting means being responsive to the predetermined tension in the portion of the strap between the first and second points thereon effectively to disconnect said restraining means from said linkage to shift said linkage into said strap-severing mode.

5. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said abutment and said gripper for movement relative to each other in a strap-tensioning direction to tension the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, a common linkage interconnecting said gripper and said blade, a manually operable actuator operatively connected to said linkage for applying actuating forces thereto at a common point therebetween, and restraining means operatively connected to said linkage for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.

6. The binder strap tensioning and severing tool set forth in claim 5, wherein said common point for applying actuating forces between said linkage and said actuator is fixed with respect to said actuator.

7. The binder strap tensioning and severing tool set forth in claim 5, wherein said common point for applying actuating forces between said linkage and said actuator is fixed with respect to said linkage.

8. The binder strap tensioning and severing tool set forth in claim 5, wherein said common point for applying actuating forces between said linkage and said actuator is fixed with respect to both said linkage and said actuator.

9. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said abutment and said gripper for movement relative to each other in a strap-tensioning direction to tension the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, a manually-operable actuator, a linkage, a first drive train interconnecting said linkage and said gripper, a second drive train interconnecting said linkage and said blade, a third drive train interconnecting said linkage and said actuator, the force for operating said gripper being exerted from said actuator through said third drive train and said linkage and said first drive train to said gripper, the force for operating said blade being exerted from said actuator through said third drive train and said linkage and said second drive train to said blade, restraining means operatively connected to said linkage for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.

10. A binder strap tensioning and severing tool comprising a frame, an abutment on said frame for engaging a binder strap at a first point thereon, a gripper on said frame for engaging the binder strap at a second point thereon, said gripper being mounted for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a link operatively connected to said gripper, an actuator operatively connected to said link for moving said gripper in the strap-tensioning direction, a blade operatively connected to said link for severing the strap along the portion thereof between the first and second points thereon, and restraining means operatively connected to said link for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, the connection between said link and said actuator being at a fixed point on said link, the connection between said link and said gripper being at a fixed point on said link, the connection between said link and said blade being at a fixed point on said link, the connection between said link and said restraining means being at a fixed point on said link, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which theoperator manually engages said actuator to apply the operating forces thereto.

1 1. The binder strap tensioning and severing tool set forth in claim 10, wherein said gripper moves with respect to said abutment along a rectilinear path.

12. A binder strap tensioning and severing tool comprising a frame, an abutment on said frame for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper on said frame for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a first pin carried by said frame at a fixed point thereon, and a first link pivotally mounted on said first pin, a second pin carried by said first link at a fixed point thereon, and a second link pivotally mounted at one point thereof on said second pin and operatively connected at another point thereof to said gripper, an actuator pivotally mounted at one point thereof on said frame and operatively connected at another point thereof to said second link for moving said gripper in the strap-tensioning direction, a blade operatively connected to said first link for severing the strap along the portion thereof between the first and second points thereon, and restraining means operatively connected to said first link for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, the connection between said second link and said actuator being at a fixed point on said second link, whereby said restraining means is overcome when a predetermined tension is produced in the length of strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.

13. The strap tensioning and severing tool set forth in claim 12, wherein said second link is pivotally mounted adjacent to one end thereof on said second pin, said second link is operatively connected adjacent to the other end thereof to said gripper, and said second link is operatively connected ad jacent to a point intermediate said ends to said actuator.

14. The strap tensioning and severing tool set forth in claim 12, wherein said actuator is pivotally mounted on said first pin.

15. The binder strap tensioning and severing tool set forth in claim 12, and further comprising a third link having one end thereof operatively connected to said second link at said fixed point on said second link, said third link having the other end thereof operatively connected to said actuator.

16. The binder strap tensioning and severing tool set forth in claim 12, and further comprising a tensioning rod carrying said gripper and operatively connected to said second link at said other point thereof.

17. A binder strap tensioning and severing tool comprising a frame, an abutment on said frame for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper on said frame for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a first pin carried by said frame at a fixed point thereon, a first link pivotally mounted on said first pin, a second pin carried by said first link at a fixed point thereon, and a second link pivotally mounted at one point thereof on said second pin and operatively connected at another point thereof to said gripper, an actuator pivotally mounted at one point thereof on said frame and operatively connected at another point thereof to said second link for moving said gripper in the strap-tensioning direction, a blade operatively connected to said first link for severing the strap along the portion thereof between the first and second points thereon, the connection between said second link and said actuator being at a fixed point on said second link, the length of the effective lever arm for applying forces between said fixed point and said gripper being fixed, the length of the effective lever arm for applying forces between said fixed point and said second pin being fixed, a roller on said first link, a detent pivotally mounted on said frame and having a recess therein, said detent being pivotal between a first position wherein said roller is seated in said recess to prevent movement of said blade and a second position wherein said roller is positioned out of said recess to permit strap-severing movement of said blade, and restraining means holding said detent in said first position thereof until a predetermined tension is produced in the length of strap between the first and second points thereof whereupon said detent is moved to the second position thereof to permit movement of said roller from said recess and subsequent strap-severing movement of said blade.

18. A binder strap tensioning and severing tool comprising a gun-shaped housing including a handle portion and a forwardly-projecting barrel portion, a manually-operable actuator mounted on said housing and movable toward and away from said handle portion, a spring operatively connected between said actuator and said housing and biased to urge said actuator away from said handle portion, an abutment on said barrel portion adjacent to the forward end thereof for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper on said barrel portion for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade on said housing for severing the strap along the portion thereof between the first and second points thereon, a common linkage interconnecting said gripper and said blade, said actuator being operatively connected to said linkage for applying forces thereto at a common point therebetween, and restraining means operatively connected to said linkage for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, whereby said restraining means is overcome when a predetermined tension is produced in the length of strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto and being independent of the force exerted by said spring.

19. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said-gripper for movement in a strap-tensioning direction withrespect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap alongthe portion thereof between the first and second points thereon, an actuator operatively connected both to said gripper and to said blade, said tool having a strap-tensioning mode wherein the force exerted by said actuator is applied to said gripper for moving said gripper in the strap-tensioning direction andhaving a strap-severing mode wherein a portion of the force exerted by said actuator is applied to said blade for moving said blade in a strap-severing direction, a detent mechanism having a first condition for placing said tool in the strap-tensioning mode thereof and having a second condition for placing said tool in the strap-severing mode thereof, and restraining means for holding said detent mechanism in said first condition until a predetermined tension is reached in the length of strap between the first and second points thereon whereupon said detent mechanism is actuated into the second condition thereof, whereby the force exerted by said actuator in the strap-tensioning mode is utilized substantially in strap-tensioning and in overcoming said restraining means and a portion of the force exerted by said actuator in the strap-severing mode is utilized to cause severing movement of said blade.

20. The binder strap tensioning and severing tool set forth in claim 19, wherein said detent mechanism includes two members, a roller on one of said members, the other of said members having a recess therein for receiving said roller, said detent mechanism being in said first condition when said roller is disposed in said recess and said detent mechanism being in said second condition when said roller is disposed out of said recess.

21. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points'thereon, an actuator operatively connected both to said gripper and to said blade, said tool having a strap-tensioning mode wherein the force exerted by said actuator is applied to said gripper for moving said gripper in the strap-tensioning direction and having a strap-severing mode wherein a portion of the force exerted by said actuator is applied to said blade for moving said blade in a strap-severing direction, a detent mechanism having a first condition for placing said tool in the strap-tensioning mode thereof and having a second condition for placing said tool in the strap-severing mode thereof, and spring biased restraining means for holding said detent mechanism in said first condition until a predetermined tension is reached in a length of strap between the first and second points thereon whereupon said detent mechanism isactuated into the second condition thereof, whereby the force exerted by said actuator in the strap-tensioning mode is utilized substantially in straptensioning and in overcoming said restraining means and a portion of the force exerted by said actuator in the strapsevering mode is utilized to cause severing movement of said blade.

22. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper for movement in a strap'tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, an actuator operatively connected both to said gripper and to said blade, said tool having a strap-tensioning mode wherein the force exerted by said actuator is applied to said gripper for moving said gripper in the strap-tensioning direction and having a strap-severing mode wherein a portion of the force exerted by said actuator is applied to said blade for moving said blade in a strap-severing direction, a detent mechanism including a movable armature and a magnet, said movable armature being operatively connected to said actuator and having a first condition for placing said tool in the strap-tensioning mode thereof and having a second condition for placing said tool in the strap-severing mode thereof, said magnet holding said armature in said first condition until a predetermined tension is reached in the length of strap between the first and second points thereon whereupon said armature is moved into the second condition thereof, whereby the force exerted by said actuator in the strap-tensioning mode is utilized substantially in strap-tensioning and in overcoming said magnet and a portion of the force exerted by said actuator in the strapsevering mode is-utilized to cause severing movement of said blade.

23. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, an actuator operatively connected both to said gripper and to said blade, said tool having a strap-tensioning mode wherein the force exerted by said actuator is applied to said gripper for moving said gripper in the strap-tensioning direction and having a strap-severing mode wherein a portion of the force exerted by said actuator is applied to said blade for moving said blade in a strap-severing direction, a detent mechanism including a piston in a cylinder having a valve therefor, said piston being operatively connected to said actuator and having a first position for placing said tool in the strap-tensioning mode thereof and having a second position for placing said tool in the strap-severing mode thereof, said cylinder carrying said piston and having the pressure therein reduced in response to-movement of said actuator to hold said piston in said first position thereof until a predetermined tension is reached in the'length of strap between the first and second points thereof, and said valve on said cylinder accommodating passage of air into said cylinder into the area of reduced pressure therein to hold said tool in said strap-tensioning mode until the predetermined tension is reached whereupon said tool is moved into said strap-severing mode thereof, whereby the force exerted by said actuator in the strap-tensioning mode is utilized substantially in strap-tensioning and in overcoming the action of said piston in said cylinder and a portion of force exerted by said actuator in the strap-severing mode is utilized to cause severing movement of said blade.

24. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means for mounting said gripper for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, linkage operatively connected to said gripper and said blade, an actuator operatively connected to said linkage, said linkage having a strap-tensioning mode wherein the force exerted by said actuator through said linkage is applied to said gripper for moving said gripper in a strap-tensioning direction and having a strap-severing mode wherein force exerted by said actuator through said linkage is applied to said blade for moving said blade in a strap-severing direction, a detent having a first condition for placing said linkage in the strap-tensioning mode thereof and having a second condition for placing said linkage in the strap-severing mode thereof, restraining means for holding said detent in said first condition until a predetermined tension is reached in the length of strap between the first and second points thereon whereupon said detent is moved into the second condition thereof, and means mounting said actuator for movement thereof between a rest position and a fullyactuated position along a predetermined regular path with respect to said abutment, the predetermined path of travel of said actuator during said strap-tensioning mode of said linkagebeing identical to the predetermined path of travel of said actuator during said strap-severing mode of said linkage thereby to provide a single predetermined path of travel for said actuator between said rest position and said fully actuated position thereof, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon'thereafter to shift said linkage from the strap-tensioning mode thereof to the strap-severing mode thereof to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.

25. A binder strap tensioning and severing tool comprising a hollow housing, an abutment on said housing for engaging a binder strap at a first point thereon, a gripper shiftably mounted on said housing for engaging the binder strap at a second point thereon, mechanism for moving said gripper relative to said abutment in a strap-tensioning direction to tension the portion of the strap between the first and second points thereon, an actuator mounted on said housing and operatively connected to said mechanism for operating said mechanism in the strap-tensioning direction, a blade shiftably mounted on said housing and operatively connected to said actuator for severing the strap along the portion thereof between the first and second points thereon, adjustable restraining means mounted in said housing and operatively connected to said blade for controlling the movement thereof, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, means for adjusting the restraining force exerted by said restraining means on said blade, said housing having a window therein and being provided with a first index marker adjacent to said window, a plate slidably mounted within said housing in position to close and to seal said window and having a second index marker thereon viewable through said window and cooperating with said first index marker, and means interconnecting said restraining means and said plate to cause movement of said plate in response to adjustment of said adjustment means, whereby the position of said plate and thereby the cooperation between said index markers provides a visual indication of the force exerted by said restraining means while sealing the window in said housing.

26. A binder strap tensioning and severing tool comprising a gun-shaped housing including a hand grip portion, a forwardly extending frame carried, by said housing, and a deflecting surface carried by said housing and extending rearwardly and upwardly with respect to said hand grip portion, an abutment on the outer end of said frame for engaging the binder strap at a first point thereon and accommodating the passage of the free end of the binder strap therepast, a gripper shiftably mounted on said frame for engaging the binder strap at a point thereon and accommodating the passage of the free end of the binder strap therethrough and along a predetermined path adjacent to said frame and along said deflecting surface and upwardly and outwardly over the upper end of said housing, mechanism for moving said gripper relative to said abutment in a straptensioning direction to tension the portion of the strap between the first and second points thereon and to feed the free end of the binder strap along the predetermined path, an actuator mounted on said housing and operatively connected to said mechanism for operating said mechanism in the straptensioning direction, a blade shiftably mounted on said frame, an elongated arm mounted on said frame and extending longitudinally thereof and operatively connected both to said blade and to said actuator, whereby operation of said actuator causes operation'of said mechanism in the strap-tensioning direction to tension the portion of the strap between the first and second points thereon and to feed the free end of the binder strap along the predetermined path and across said deflecting surface and thereafter operating said blade via said arm to effect severing of the binder strap without interfering with the passage of the free end of the binder strap along the predetermined path therefor.

27. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, said gripper being mounted for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a linkage operatively connected to said gripper, manually operable actuator operatively connected to said linkage for moving said gripper in the strap-tensioning direction, a blade operatively connected to said linkage for severing the strap along the portion thereof between the first and second points thereon, and restraining means operatively connected to said linkage for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, the connection between said linkage and said actuator being at a fixed point on said linkage, the effective length of the lever arm for applying forces between said fixed point and said gripper being fixed, the effective length of the lever arm for applying forces between said fixed point and said restraining means being fixed, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.

' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 661 187 I Dated May 1972 Inventor(s) Jack E. Caveney and Roy A. Moodv It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

IN THE ABSTRACT, Line, 6, after "movement" insert a semicolon.

Column 8, line 70, delete "end" first and second occurrences).

Column 9, line 28, change "relive" to relieve Column 10, line 8, change 'encl'ienced" to enhanced I Signed and sealed this 15th day of May 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTI'SCHALK Attesting Officer I Commissioner of Patents FORM PC1-1050 (10-69) uscoMM-Dc 60376-p69 U.Sl GOVERNMENT PRlNTlNG OFFICE: [969 6-366-334 

1. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper for movement in a strap-tensioning direction with respect to said abutment for tensioniNg the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, linkage operatively connected to said gripper and said blade, an actuator operatively connected to said linkage, said linkage having a strap-tensioning mode wherein the force exerted by said actuator through said linkage is applied to said gripper for moving said gripper in a strap-tensioning direction and having a strap-severing mode wherein force exerted by said actuator through said linkage is applied to said blade for moving said blade in a strap-severing direction, and restraining means for holding said linkage in said strap-tensioning mode until a predetermined tension is reached in the length of the strap between the first and second points thereon whereupon said linkage is shifted into said strapsevering mode thereof, means mounting said actuator for movement thereof between a rest position and a fully-actuated position along a predetermined regular path with respect to said abutment, the predetermined path of travel of said actuator during said strap-tensioning mode of said linkage being identical to the predetermined path of travel of said actuator during said strapsevering mode of said linkage thereby to provide a single predetermined path of travel for said actuator between said rest position and said fully actuated position thereof, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon thereafter to shift said linkage from the straptensioning mode thereof to the strap-severing mode thereof to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.
 2. The binder strap tensioning and severing tool set forth in claim 1, wherein the predetermined path of said actuator from said rest position to said fully-actuated position is a pivotal path about a point fixed with respect to said abutment.
 3. The binder strap tensioning and severing tool set forth in claim 1, wherein said restraining means is adjustable so as to adjust the predetermined tension in the portion of the strap between the first and second points thereon causing actuation of said blade to effect severing of the strap.
 4. The binder strap tensioning and severing tool set forth in claim 1, and further comprising releasable interconnecting means between said linkage and said restraining means, said releasable interconnecting means being responsive to the predetermined tension in the portion of the strap between the first and second points thereon effectively to disconnect said restraining means from said linkage to shift said linkage into said strap-severing mode.
 5. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said abutment and said gripper for movement relative to each other in a strap-tensioning direction to tension the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, a common linkage interconnecting said gripper and said blade, a manually operable actuator operatively connected to said linkage for applying actuating forces thereto at a common point therebetween, and restraining means operatively connected to said linkage for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon thEreafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.
 6. The binder strap tensioning and severing tool set forth in claim 5, wherein said common point for applying actuating forces between said linkage and said actuator is fixed with respect to said actuator.
 7. The binder strap tensioning and severing tool set forth in claim 5, wherein said common point for applying actuating forces between said linkage and said actuator is fixed with respect to said linkage.
 8. The binder strap tensioning and severing tool set forth in claim 5, wherein said common point for applying actuating forces between said linkage and said actuator is fixed with respect to both said linkage and said actuator.
 9. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said abutment and said gripper for movement relative to each other in a strap-tensioning direction to tension the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, a manually-operable actuator, a linkage, a first drive train interconnecting said linkage and said gripper, a second drive train interconnecting said linkage and said blade, a third drive train interconnecting said linkage and said actuator, the force for operating said gripper being exerted from said actuator through said third drive train and said linkage and said first drive train to said gripper, the force for operating said blade being exerted from said actuator through said third drive train and said linkage and said second drive train to said blade, restraining means operatively connected to said linkage for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.
 10. A binder strap tensioning and severing tool comprising a frame, an abutment on said frame for engaging a binder strap at a first point thereon, a gripper on said frame for engaging the binder strap at a second point thereon, said gripper being mounted for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a link operatively connected to said gripper, an actuator operatively connected to said link for moving said gripper in the strap-tensioning direction, a blade operatively connected to said link for severing the strap along the portion thereof between the first and second points thereon, and restraining means operatively connected to said link for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, the connection between said link and said actuator being at a fixed point on said link, the connection between said link and said gripper being at a fixed point on said link, the connection between said link and said blade being at a fixed point on said link, the connection between said link and said restraining means being at a fixed point on said link, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.
 11. The binder strap tensioning and severing tool set forth in claim 10, wherein said gripper moves with respect to said abutment along a rectilinear path.
 12. A binder strap tensioning and severing tool comprising a frame, an abutment on said frame for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper on said frame for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a first pin carried by said frame at a fixed point thereon, and a first link pivotally mounted on said first pin, a second pin carried by said first link at a fixed point thereon, and a second link pivotally mounted at one point thereof on said second pin and operatively connected at another point thereof to said gripper, an actuator pivotally mounted at one point thereof on said frame and operatively connected at another point thereof to said second link for moving said gripper in the strap-tensioning direction, a blade operatively connected to said first link for severing the strap along the portion thereof between the first and second points thereon, and restraining means operatively connected to said first link for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, the connection between said second link and said actuator being at a fixed point on said second link, whereby said restraining means is overcome when a predetermined tension is produced in the length of strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.
 13. The strap tensioning and severing tool set forth in claim 12, wherein said second link is pivotally mounted adjacent to one end thereof on said second pin, said second link is operatively connected adjacent to the other end thereof to said gripper, and said second link is operatively connected adjacent to a point intermediate said ends to said actuator.
 14. The strap tensioning and severing tool set forth in claim 12, wherein said actuator is pivotally mounted on said first pin.
 15. The binder strap tensioning and severing tool set forth in claim 12, and further comprising a third link having one end thereof operatively connected to said second link at said fixed point on said second link, said third link having the other end thereof operatively connected to said actuator.
 16. The binder strap tensioning and severing tool set forth in claim 12, and further comprising a tensioning rod carrying said gripper and operatively connected to said second link at said other point thereof.
 17. A binder strap tensioning and severing tool comprising a frame, an abutment on said frame for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper on said frame for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a first pin carried by said frame at a fixed point thereon, a first link pivotally mounted on said first pin, a second pin carried by said first link at a fixed point thereon, and a second link pivotally mounted at one point thereof on said second pin and operatively connected at another point thereof to said gripper, an actuator pivotally mounted at one point Thereof on said frame and operatively connected at another point thereof to said second link for moving said gripper in the strap-tensioning direction, a blade operatively connected to said first link for severing the strap along the portion thereof between the first and second points thereon, the connection between said second link and said actuator being at a fixed point on said second link, the length of the effective lever arm for applying forces between said fixed point and said gripper being fixed, the length of the effective lever arm for applying forces between said fixed point and said second pin being fixed, a roller on said first link, a detent pivotally mounted on said frame and having a recess therein, said detent being pivotal between a first position wherein said roller is seated in said recess to prevent movement of said blade and a second position wherein said roller is positioned out of said recess to permit strap-severing movement of said blade, and restraining means holding said detent in said first position thereof until a predetermined tension is produced in the length of strap between the first and second points thereof whereupon said detent is moved to the second position thereof to permit movement of said roller from said recess and subsequent strap-severing movement of said blade.
 18. A binder strap tensioning and severing tool comprising a gun-shaped housing including a handle portion and a forwardly-projecting barrel portion, a manually-operable actuator mounted on said housing and movable toward and away from said handle portion, a spring operatively connected between said actuator and said housing and biased to urge said actuator away from said handle portion, an abutment on said barrel portion adjacent to the forward end thereof for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper on said barrel portion for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade on said housing for severing the strap along the portion thereof between the first and second points thereon, a common linkage interconnecting said gripper and said blade, said actuator being operatively connected to said linkage for applying forces thereto at a common point therebetween, and restraining means operatively connected to said linkage for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, whereby said restraining means is overcome when a predetermined tension is produced in the length of strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto and being independent of the force exerted by said spring.
 19. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, an actuator operatively connected both to said gripper and to said blade, said tool having a strap-tensioning mode wherein the force exerted by said actuator is applied to said gripper for moving said gripper in the strap-tensioning direction and having a strap-severing mode wherein a portion of the force exerted by said actuator is applied to said blade for moving said blade in a strap-severing direction, a detent mechanism haviNg a first condition for placing said tool in the strap-tensioning mode thereof and having a second condition for placing said tool in the strap-severing mode thereof, and restraining means for holding said detent mechanism in said first condition until a predetermined tension is reached in the length of strap between the first and second points thereon whereupon said detent mechanism is actuated into the second condition thereof, whereby the force exerted by said actuator in the strap-tensioning mode is utilized substantially in strap-tensioning and in overcoming said restraining means and a portion of the force exerted by said actuator in the strap-severing mode is utilized to cause severing movement of said blade.
 20. The binder strap tensioning and severing tool set forth in claim 19, wherein said detent mechanism includes two members, a roller on one of said members, the other of said members having a recess therein for receiving said roller, said detent mechanism being in said first condition when said roller is disposed in said recess and said detent mechanism being in said second condition when said roller is disposed out of said recess.
 21. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, an actuator operatively connected both to said gripper and to said blade, said tool having a strap-tensioning mode wherein the force exerted by said actuator is applied to said gripper for moving said gripper in the strap-tensioning direction and having a strap-severing mode wherein a portion of the force exerted by said actuator is applied to said blade for moving said blade in a strap-severing direction, a detent mechanism having a first condition for placing said tool in the strap-tensioning mode thereof and having a second condition for placing said tool in the strap-severing mode thereof, and spring biased restraining means for holding said detent mechanism in said first condition until a predetermined tension is reached in a length of strap between the first and second points thereon whereupon said detent mechanism is actuated into the second condition thereof, whereby the force exerted by said actuator in the strap-tensioning mode is utilized substantially in strap-tensioning and in overcoming said restraining means and a portion of the force exerted by said actuator in the strap-severing mode is utilized to cause severing movement of said blade.
 22. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, an actuator operatively connected both to said gripper and to said blade, said tool having a strap-tensioning mode wherein the force exerted by said actuator is applied to said gripper for moving said gripper in the strap-tensioning direction and having a strap-severing mode wherein a portion of the force exerted by said actuator is applied to said blade for moving said blade in a strap-severing direction, a detent mechanism including a movable armature and a magnet, said movable armature being operatively connected to said actuator and having a first condition for placing said tool in the strap-tensioning mode thereof and having a second condition for placing said tool in the strap-severing mode thereof, said magnet holding said Armature in said first condition until a predetermined tension is reached in the length of strap between the first and second points thereon whereupon said armature is moved into the second condition thereof, whereby the force exerted by said actuator in the strap-tensioning mode is utilized substantially in strap-tensioning and in overcoming said magnet and a portion of the force exerted by said actuator in the strap-severing mode is utilized to cause severing movement of said blade.
 23. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means mounting said gripper for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, an actuator operatively connected both to said gripper and to said blade, said tool having a strap-tensioning mode wherein the force exerted by said actuator is applied to said gripper for moving said gripper in the strap-tensioning direction and having a strap-severing mode wherein a portion of the force exerted by said actuator is applied to said blade for moving said blade in a strap-severing direction, a detent mechanism including a piston in a cylinder having a valve therefor, said piston being operatively connected to said actuator and having a first position for placing said tool in the strap-tensioning mode thereof and having a second position for placing said tool in the strap-severing mode thereof, said cylinder carrying said piston and having the pressure therein reduced in response to movement of said actuator to hold said piston in said first position thereof until a predetermined tension is reached in the length of strap between the first and second points thereof, and said valve on said cylinder accommodating passage of air into said cylinder into the area of reduced pressure therein to hold said tool in said strap-tensioning mode until the predetermined tension is reached whereupon said tool is moved into said strap-severing mode thereof, whereby the force exerted by said actuator in the strap-tensioning mode is utilized substantially in strap-tensioning and in overcoming the action of said piston in said cylinder and a portion of force exerted by said actuator in the strap-severing mode is utilized to cause severing movement of said blade.
 24. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, means for mounting said gripper for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a blade for severing the strap along the portion thereof between the first and second points thereon, linkage operatively connected to said gripper and said blade, an actuator operatively connected to said linkage, said linkage having a strap-tensioning mode wherein the force exerted by said actuator through said linkage is applied to said gripper for moving said gripper in a strap-tensioning direction and having a strap-severing mode wherein force exerted by said actuator through said linkage is applied to said blade for moving said blade in a strap-severing direction, a detent having a first condition for placing said linkage in the strap-tensioning mode thereof and having a second condition for placing said linkage in the strap-severing mode thereof, restraining means for holding said detent in said first condition until a predetermined tension is reached in the length of strap between the first and second points thereon whereupon said detent is moved into the second condition thereof, and means mounting said actuator for movement thereof between a rest position and a fully-actuated position along a predetermined regular path with respect to said abutment, the predetermined path of travel of said actuator during said strap-tensioning mode of said linkage being identical to the predetermined path of travel of said actuator during said strap-severing mode of said linkage thereby to provide a single predetermined path of travel for said actuator between said rest position and said fully actuated position thereof, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon thereafter to shift said linkage from the strap-tensioning mode thereof to the strap-severing mode thereof to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto.
 25. A binder strap tensioning and severing tool comprising a hollow housing, an abutment on said housing for engaging a binder strap at a first point thereon, a gripper shiftably mounted on said housing for engaging the binder strap at a second point thereon, mechanism for moving said gripper relative to said abutment in a strap-tensioning direction to tension the portion of the strap between the first and second points thereon, an actuator mounted on said housing and operatively connected to said mechanism for operating said mechanism in the strap-tensioning direction, a blade shiftably mounted on said housing and operatively connected to said actuator for severing the strap along the portion thereof between the first and second points thereon, adjustable restraining means mounted in said housing and operatively connected to said blade for controlling the movement thereof, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, means for adjusting the restraining force exerted by said restraining means on said blade, said housing having a window therein and being provided with a first index marker adjacent to said window, a plate slidably mounted within said housing in position to close and to seal said window and having a second index marker thereon viewable through said window and cooperating with said first index marker, and means interconnecting said restraining means and said plate to cause movement of said plate in response to adjustment of said adjustment means, whereby the position of said plate and thereby the cooperation between said index markers provides a visual indication of the force exerted by said restraining means while sealing the window in said housing.
 26. A binder strap tensioning and severing tool comprising a gun-shaped housing including a hand grip portion, a forwardly extending frame carried by said housing, and a deflecting surface carried by said housing and extending rearwardly and upwardly with respect to said hand grip portion, an abutment on the outer end of said frame for engaging the binder strap at a first point thereon and accommodating the passage of the free end of the binder strap therepast, a gripper shiftably mounted on said frame for engaging the binder strap at a point thereon and accommodating the passage of the free end of the binder strap therethrough and along a predetermined path adjacent to said frame and along said deflecting surface and upwardly and outwardly over the upper end of said housing, mechanism for moving said gripper relative to said abutment in a strap-tensioning direction to tension the portion of the strap between the first and second points thereon and to feed the free end of the binder strap along the predetermined path, an actuator mounted on said housing and operatively connected to said mechanism for operating said mechanism in the strap-tensioning direction, a blade shiftably mounted on said frame, an elongated arm mounted on said frame and extending longitudinally thereof and operatively connected both to said bLade and to said actuator, whereby operation of said actuator causes operation of said mechanism in the strap-tensioning direction to tension the portion of the strap between the first and second points thereon and to feed the free end of the binder strap along the predetermined path and across said deflecting surface and thereafter operating said blade via said arm to effect severing of the binder strap without interfering with the passage of the free end of the binder strap along the predetermined path therefor.
 27. A binder strap tensioning and severing tool comprising an abutment for engaging a binder strap at a first point thereon, a gripper for engaging the binder strap at a second point thereon, said gripper being mounted for movement in a strap-tensioning direction with respect to said abutment for tensioning the portion of the strap between the first and second points thereon, a linkage operatively connected to said gripper, manually operable actuator operatively connected to said linkage for moving said gripper in the strap-tensioning direction, a blade operatively connected to said linkage for severing the strap along the portion thereof between the first and second points thereon, and restraining means operatively connected to said linkage for controlling the movement thereof to effect operation of said blade, said restraining means preventing actuation of said blade in response to movement of said actuator until said restraining means has been overcome, the connection between said linkage and said actuator being at a fixed point on said linkage, the effective length of the lever arm for applying forces between said fixed point and said gripper being fixed, the effective length of the lever arm for applying forces between said fixed point and said restraining means being fixed, whereby said restraining means is overcome when a predetermined tension is produced in the portion of the strap between the first and second points thereon thereafter to cause actuation of said blade to effect severing of the strap, said predetermined tension being independent of the point at which the operator manually engages said actuator to apply the operating forces thereto. 